Recently, with the development of humanization and facilitation, touch panels, display panels and display devices with touch function become more and more popular. Based on different working principles, there exist several types of touch panels, such as a resistive-type touch panel, a capacitive-type touch panel, and an electromagnetic-type touch panel. The resistive-type touch panel and the capacitive-type touch panel may be operated by a hand directly. In the case that a stylus is adopted to write, it is difficult to accurately distinguish a touch of the hand from that of the stylus since the hand generally contacts the touch panel. The electromagnetic-type touch panel mainly includes multiple electromagnetic induction coils or antennas, arranged in an X-direction and in a Y-direction, and a positioning device (e.g., an electromagnetic stylus). A location of an electromagnetic stylus can be accurately recognized by the electromagnetic-type touch panel even if the hand is on the panel.
FIG. 1a is a structural schematic diagram of a conventional electromagnetic-type touch panel. As can be seen from FIG. 1a, the electromagnetic-type touch panel includes: first coils 11 (including 11-1, 11-2, 11-3 . . . , 11-48) arranged in an X-direction and extending in a Y-direction, and second coils 12 (including 12-1, 12-2, 12-3 . . . , 12-48) arranged in the Y-direction and extending in the X-direction. Normally, the first coils 11 and the second coils 12 are crossed with each other and are insulated from each other, and both the first coils 11 and the second coils 12 are disposed on a substrate (not shown in FIG. 1a). Taking the first coils 11 as an example and in conjunction with FIGS. 1b and 1c, a method for driving and detecting the conventional touch panel is described. After being applied with a drive signal and emitting an electromagnetic signal, each first coil receives an electromagnetic signal reflected by an electromagnetic stylus and generates an induction signal. The first coil 11-1 is applied with the driving signal and thereby emits an electromagnetic signal. The electromagnetic stylus 13 receives the electromagnetic signal emitted by the first coil 11-1, and a resonance circuit (e.g., an LC resonance circuit) in the electromagnetic stylus 13 generates, through resonance, an electromagnetic signal (i.e., a reflected signal) having a same frequency as the electromagnetic signal emitted by the first coil 11-1, and emits the generated reflected signal. The first coil 11-1 generates an induced signal (which is generally an induced voltage) after receiving the electromagnetic signal reflected by the electromagnetic stylus. Similarly, the first coils 11-2, 11-3, . . . , 11-48 each generates an induced signal. Thus, 48 induced signals are generated. Then a function fitting (e.g., a quadratic function fitting) is performed on the 48 induced signals, and a peak (Xp) of a fitted curve is taken as an X-direction coordinate of a touch position of the electromagnetic stylus. A Y-direction coordinate of the touch position of the electromagnetic stylus may be determined similarly.
With the above touch panel and the method for driving and detecting the touch panel, the touch position of the electromagnetic stylus may be determined properly. However, the driving and detecting efficiency needs to be improved.